Vibrator, vibration type driving apparatus and manufacturing method of vibrator

ABSTRACT

A vibrator includes an elastic body bonded to an electrical-mechanical energy converting element and including at least two contact parts, in which the at least two contact parts have convex shapes, shapes of surfaces of the at least two contact parts are part of spherical shapes, and rising directions of the at least two contact parts toward a member to be driven when the member is driven are different.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vibrator, a vibration type drivingapparatus and a manufacturing method of the vibrator.

2. Description of the Related Art

Conventionally, a vibration type driving apparatus (for example,ultrasonic motor) that drives a moving body by vibration generated by anelastic body is known.

In the vibration type driving apparatus, a vibrator that includes anelectrical-mechanical energy converting element (for example,piezoelectric element) and an elastic body (elastic body mainly made ofmetal) bonded with the electrical-mechanical energy converting elementexcites a plurality of vibration modes.

The plurality of vibrations are combined to generate an ellipticalmotion on a surface of the elastic body, and a member to be driven thatis in contact with the elastic body is relatively driven.

Various forms of the vibration type driving apparatus are proposed. Forexample, in relation to a vibration wave motor that rotates and drives alens barrel of a camera, a ring-shaped vibration wave motor and arod-shaped rotary vibration wave motor are proposed.

A large number of devised motor configurations and forms are furtherproposed, such as a vibration wave motor formed as a rotary actuatorincluding a plurality of plate-shaped elastic bodies on thecircumference, in which a vibrating part is formed by a thin plate partand a projection part.

A large number of linear type vibration wave motors are also proposed,in which the plate type elastic bodies come into contact with a linearslider to linearly drive the elastic bodies.

A vibration type driving apparatus disclosed in Japanese PatentApplication Laid-Open No. 2004-304887 will be illustrated as an exampleto describe a summary of a configuration of the vibration wave motorincluding the plate type elastic body.

The vibration type driving apparatus includes a vibrator and a sliderthat comes into contact with the vibrator.

The vibrator is formed by bonding an electrical-mechanical energyconverting element (for example, piezoelectric element) to a plate typeelastic body including a flat-plate vibrating body provided with twoprojection parts on one of the surfaces.

If AC electric fields at different phases are applied to thepiezoelectric element, two out-of-plane bending vibrations are excitedin the vibrator, and an elliptical motion is generated at tips of thetwo projection parts.

As a result, the slider that comes into contact with the projectionparts receives frictional driving force and is driven in one direction.

SUMMARY OF THE INVENTION

However, if there are processing accuracy variations in the dimension ofthe projection parts in the elastic body of the vibration type drivingapparatus, contact areas and contact directions of the plurality ofprojection part tips relative to the moving body vary in the drivingapparatus, and the driving performance is adversely affected.

Therefore, highly accurate processing is necessary to arrange aplurality of projection part contact surfaces on the same plane and toequalize areas of the projection part contact surfaces. This causes anincrease in the cost.

When post-processing is applied to the tips of the projection partsbased on a method, such as lap processing and grinding processing, forhighly accurate finish as illustrated in FIG. 19, the plurality ofprojection part contact surfaces can be relatively easily processed onthe same plane in terms of the flatness.

However, to equalize the areas of the post-processed projection partcontact surfaces, lapping is performed through a state illustrated inFIG. 20, i.e., a state in which lapping of one of the projection partsis completed, but lapping of the other projection part is not completed.Therefore, one of the projection parts needs to be lapped more thannecessary, and more lap time is required accordingly. This causes anincrease in the cost.

An aspect of the present invention relates to a vibrator, a vibrationtype driving apparatus or a manufacturing method of the vibrator thatcan improve driving performance by equalizing contact areas relative toa moving body, without the necessity to highly accurately processprojection parts in the vibrator.

An aspect of the present invention relates to a vibrator including anelastic body bonded to an electrical-mechanical energy convertingelement and including at least two contact parts, in which the at leasttwo contact parts have convex shapes, shapes of surfaces of the at leasttwo contact parts are part of spherical shapes, and rising directions ofthe at least two contact parts toward a member to be driven when themember is driven are different.

An aspect of the present invention relates to a vibrator including: anelectrical-mechanical energy converting element; and an elastic bodybonded to the electrical-mechanical energy converting element andincluding contact parts, wherein each of the parts has convex shape inwhich part of spherical shape has been removed.

An aspect of the present invention relates to a vibration type drivingapparatus including: the vibrator described above; an attachment basemember that supports the vibrator; and an equalize member arrangedbetween the vibrator and the attachment base member.

An aspect of the present invention relates to a manufacturing method ofa vibrator, the manufacturing method including processing a tip of acontact part arranged on an elastic body of the vibrator by lapping orgrinding processing so that part of the tip has a plane shape in part ofa spherical shape.

An aspect of the present invention relates to a manufacturing method ofa vibrator, the manufacturing method including processing a tip of afirst contact part arranged on an elastic body and a tip of a secondcontact part arranged on the elastic body by lapping or grindingprocessing so that each of the tip of the first contact part and the tipof the second contact part has plane shape in part of spherical shape.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top view of a configuration example of a flat-platevibrator.

FIG. 1B is a front view of the configuration example of the flat-platevibrator.

FIG. 2 is a diagram illustrating a configuration example of an elasticbody of the plate vibrator.

FIG. 3 is a diagram illustrating a configuration of main parts of avibration type driving apparatus.

FIG. 4 is a diagram illustrating the configuration of FIG. 3 byexploding each component.

FIG. 5A is a left view of rising directions of elastic body projectionparts of the plate vibrator.

FIG. 5B is a front view of the rising directions of the elastic bodyprojection parts of the plate vibrator.

FIG. 6 is a diagram for describing vibration modes of the flat-platevibrator.

FIG. 7 is a diagram illustrating a configuration example of the elasticbody of the plate vibrator.

FIG. 8 is a diagram illustrating lapping or grinding processing of theelastic body in a manufacturing method of the vibration type drivingapparatus.

FIG. 9A is an exploded left view of the elastic body of FIG. 8.

FIG. 9B is an exploded front view of the elastic body of FIG. 8.

FIG. 10 is a diagram illustrating a configuration of main parts of thevibration type driving apparatus.

FIG. 11 is a diagram illustrating the configuration of FIG. 10 byexploding each component.

FIG. 12 is a diagram illustrating a configuration example of the elasticbody of the plate vibrator.

FIG. 13 is a diagram illustrating a configuration of main parts of thevibration type driving apparatus.

FIG. 14 is a diagram illustrating a stator portion of the vibration typedriving apparatus.

FIG. 15 is a diagram illustrating lapping or grinding processing of theelastic body.

FIG. 16 is an exploded view of the elastic body of FIG. 15.

FIG. 17 is a diagram illustrating a sheet-shaped elastic body.

FIG. 18 is a diagram illustrating the sheet-shaped elastic body.

FIG. 19 is a diagram illustrating lapping or grinding processing of theelastic body.

FIG. 20 is a diagram illustrating a state in the middle of the lappingor grinding processing of the elastic body.

DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail in accordance with the accompanying drawings.

First Embodiment

A configuration example of a vibrator of a vibration type drivingapparatus according to the present invention will be described in afirst embodiment with reference to FIGS. 1A to 6.

The vibration type driving apparatus of the present embodiment is bondedto an electrical-mechanical energy converting element and includes anelastic body with one or more contact parts. The contact parts of theelastic body are brought into frictional contact with a member to bedriven, and vibration generated by the elastic body relatively moves themember to be driven.

Specifically, as illustrated in FIGS. 1A and 1B, a flat-plate vibrator 1includes: an elastic body 2; a piezoelectric element 3 as an example ofthe electrical-mechanical energy converting element; and a flexibleprinted circuit (FPC) 4 that supplies power to the piezoelectric element3.

The piezoelectric element 3 is fixed to the elastic body 2 by adhesion,etc.

The elastic body 2 includes: a vibration part 2-3 that vibrates alongwith the piezoelectric element 3; supporting parts 2-5 substantiallyisolated from the vibration of the vibration part; and connection parts2-4 that connect the vibration part 2-3 and the supporting parts 2-5, inwhich one end follows the vibration of the vibration part 2-3, and theother end functions not to transmit the vibration to the supporting part2-5.

Long round holes 2-6 are formed on the supporting parts 2-5, and pins 8described later (FIGS. 3 and 4) are fitted to the long round holes 2-6in the longitudinal direction at a predetermined clearance.

The contact parts have spherical shapes convex toward the member to bedriven. More specifically, the contact parts have convex shapes, and theshapes of the surfaces form part of the spherical shapes. Specifically,as shown in FIGS. 1A, 1B and 2, the vibration part 2-3 is provided witha plurality of projection parts 2-2 as frictional contact parts, on theother side of the fixed surface of the piezoelectric element 3. Thepresent embodiment has a feature that the tip of the projection part 2-2is shaped to form part of the sphere.

The shape of a cross section H-H perpendicular to the longitudinal axisof the projection part 2-2 is not limited to a circular shape, but canbe other shapes such as a polygon that can be formed.

The elastic body 2 can be formed by any processing method, such aspressing, cutting, drawing and extrusion. An optimal processing methodcan be adopted according to the manufacturing cost and requiredaccuracy.

As illustrated in FIGS. 3 and 4, the flat-plate vibrator 1 is mounted onan equalize plate 9 across a felt 5, and the equalize plate 9 issupported by an attachment base member 6 across a cylindrical shaft 10.Therefore, the attachment base member 6 supports the vibrator 1. In thepresent embodiment, the equalize plate 9 and the cylindrical shaft 10form an equalize member. The equalize member is arranged between thevibrator 1 and the attachment base member 6 and is a member forequalizing the load on the plurality of projection parts 2-2. In thepresent invention, the equalization of the load includes not onlycomplete equalization of the load, but also substantial equalization ofthe load and reduction in variations of load distribution as a result ofthe arrangement of the equalize member.

In the present embodiment, the felt 5 is arranged between the equalizeplate 9 and the vibrator 1 that form the equalize member. The felt 5functions as a vibration isolating member for cutting off thetransmission of vibration between vibrator 1 and the equalize plate 9. Vgrooves are formed on a lower surface of the equalize plate 9 and on anupper surface of the attachment base member 6, and the shaft 10 isfitted to the V grooves. In this way, the equalize plate 9 and theflat-plate vibrator 1 are equalized in an A direction of FIG. 3, and themovement of the equalize plate 9 in a B direction is restricted.

The pins 8 are set up on the attachment base member 6 and are fitted tothe long round holes 2-6 of the elastic body 2 to restrict the movementof the flat-plate vibrator 1 in the B direction at a predeterminedmargin (play).

The margin can equalize the flat-plate vibrator 1 in the A direction. Aslider (member to be driven) 7 includes, on a surface, a frictionalcontact part 7-1 applied with antiwear treatment. The frictional contactpart 7-1 is arranged to face and come into contact with the frictionalcontact surface of the vibrator 1.

A spring element (not illustrated) provides appropriate pressurizationforce to the flat-plate vibrator 1 and the slider 7.

In the present embodiment, the tip of the projection part 2-2 is shapedto form part of the sphere.

Therefore, the plurality of projection parts 2-2 come into contact withthe slider 7 at equal force, and the contact areas are the same,regardless of the rising directions of the projection parts 2-2 due toerrors in manufacturing as illustrated in FIGS. 5A and 5B. In thepresent invention, the “same” denotes not only exactly the same, butalso substantially the same.

Although the contact part of the sphere and the plane is geometrically apoint, it should be noted that the contact part actually has some areadue to the flexure of the material.

When an AC electric field is applied from the FPC 4 to the piezoelectricelement 3, a first vibration mode (mode 1) and a second vibration mode(mode 2) as illustrated in FIG. 6 are excited in the flat-plate vibrator1.

The mode 1 is a primary out-of-plate flexing vibration mode in a lateraldirection of the flat-plate vibrator 1, the mode including two nodallines (linear parts as nodes of vibration) 11 and 12 in a directionorthogonal to the lateral direction in FIG. 6, in which center parts ofthe nodal lines 11 and 12 serve as antinodes of vibration.

Meanwhile, the mode 2 is a secondary out-of-plane flexing vibration modein a longitudinal direction of the flat-plate vibrator 1, the modeincluding three nodal lines (13, 14 and 15) orthogonal to the two nodallines 11 and 12 in FIG. 6.

As illustrated in FIG. 6, the projection parts 2-2 are set tosubstantially coincide with positions of nodal lines 14 and 15.Therefore, when the mode 2 is excited, vibration amplitude in a Zdirection of the tips (upper surfaces) of the projection parts 2-2 issubstantially zero, and only vibration amplitude in an X direction isgenerated.

When the mode 1 is excited, vibration amplitude of the projection parts2-2 in the X direction is substantially zero, and vibration amplitude inthe Z direction becomes the maximum.

Therefore, if these two vibration modes are excited at the same time toappropriately adjust and combine the phases of vibration, an ellipticalmotion is generated at the projection parts 2-2 formed on the elasticbody 2.

As a result, if the slider 7 as illustrated in FIG. 3 comes into contactwith the projection parts, the slider 7 is driven in the direction ofthe arrow B due to frictional force based on the elliptical motion.

According to the configuration, the tips of the elastic body projectionparts as frictional contact parts in the vibration type drivingapparatus are shaped to form part of the spheres. Therefore, the contactareas relative to the moving body are equalized in the motor withouthighly accurate processing of the projection parts, and deterioration inthe motor characteristics can be prevented. An increase in the costassociated with highly accurate projection parts can also be prevented.

Second Embodiment

A configuration example of a manufacturing method of a vibrator in avibration type driving apparatus will be described in a secondembodiment with reference to FIGS. 7 to 11, 17 and 18.

The elastic body of the present embodiment is obtained by applyingpost-processing to the elastic body of the first embodiment to changethe shape.

In the present embodiment, the tips of the plurality of projection parts2-2 (tip shapes form part of sphere) are processed by grinding orlapping processing for the arrangement on the same plane as illustratedin FIG. 7, and the shapes of the cut areas (surfaces exposed by cuttingoff part of the projection parts) are circular shapes with the samediameter. Therefore, the projection parts 2-2 have convex shapes, andpart of the surface of the convex shape is removed in part of eachspherical shape.

It is known that the antiwear property is improved by applying grindingor lapping processing to the projection parts 2-2 depending on thematerials of the elastic body 2 and the slider 7 and depending on thestate of the surface of the contact parts. The present embodiment issuitable for such a case.

In association with the tip shape of the projection parts 2-2, theequalize configuration of the flat-plate vibrator 1 is also different.

The foregoing two points are the differences from the first embodiment.In place of the long round holes 2-6, round holes 2-7 with apredetermined play (clearance) relative to the outside diameters of thepins 8 are formed on the elastic body 2, and this is associated with theequalize configuration (described later).

In FIGS. 8, 9A and 9B, a lap disc or grinding disc 21 rotates in an Edirection. The elastic body 2 is set so that the plane part issubstantially parallel to the lap disc 21, the tips of the projectionparts 2-2 come into contact with the lap disc 21, and equal load isimposed on the plurality of projection parts 2-2 in a C direction ofFIG. 8.

To prevent inequality in the amount of cutting due to the difference inthe peripheral length in the radial direction of the lap disc, arotation mechanism (not illustrated) rotates the elastic body 2 in a Ddirection for the scraping.

As a result of the processing of the tips of the projection parts 2-2,the tips are on the same plane, and the tips have circular shapes withthe same area as illustrated in FIGS. 9A and 9B, regardless of therising directions of the projection parts 2-2 due to errors inmanufacturing.

If the elastic body 2 is manufactured by progressing-type pressing, aplurality of elastic bodies 2 are integrated and continuous in a sheetshape, forming a sheet-shaped member in the middle of the manufacturingprocess as illustrated in FIGS. 17 and 18. The lapping or grindingprocessing can also be applied in this format.

In this case, a connection part that connects the elastic bodies and aframe part is included. The connection part can have a configuration asillustrated in FIG. 18 for example, in which the connection part is onone axis in a substantially perpendicular direction of the arrangementof the contact parts.

The format of FIG. 17 is developed in FIG. 18. A connection part 42 ofthe elastic body 2 and the frame part 41 is formed to coincide with aperpendicular bisector of a line connecting the projection parts 2-2 andto have proper torsional rigidity.

As a result, when load in the C direction is imposed on the elastic body2 during lapping, the connection part 42 serves as a rotation centeraxis. The elastic body 2 easily follows the lap disc 21, and equal loadcan be more easily imposed on a plurality of projection parts 2-2 in oneelastic body 2.

In this way, the lapping or grinding processing in the sheet form caneliminate the process of aligning and arranging single elastic bodies 2on the lap disc 21.

As illustrated in FIGS. 10 and 11, the flat-plate vibrator 1 is mountedon the equalize plate 9 across the felt 5, and the equalize plate 9 issupported by the attachment base member 6 across the sphere 25.

Conical grooves are formed on the lower surface of the equalize plate 9and on the upper surface of the attachment base member 6, and the sphere25 is fitted to the conical grooves. In this way, the equalize plate 9and the flat-plate vibrator 1 are equalized in an F direction of FIG.10, and movement of the equalize plate 9 in the B direction isrestricted.

Although the F direction is expressed by two arrows with a 90°difference in the orientation, the F direction denotes the entiredirection obtained by rotating one arrow 360° around the vertical axis.

The pins 8 are fitted to the round holes 2-7 of the elastic body 2, andthe movement of the flat-plate vibrator 1 in the B direction isrestricted at a predetermined margin (play).

The margin can equalize the flat-plate vibrator 1 in the F direction.The slider 7 includes, on a surface, the frictional contact part 7-1applied with antiwear treatment. The frictional contact part 7-1 isarranged to face and come into contact with the frictional contactsurface of the vibrator 1.

A spring element (not illustrated) provides appropriate pressurizationforce to the flat-plate vibrator 1 and the slider 7.

As a result, all tips of the projection parts 2-2 follow the frictionalcontact part 7-1, and equal contact area and equal welding pressure aresecured at the contact parts.

In this way, the tips of the plurality of projection parts 2-2 are onthe same plane and have circular shapes with the same area in thepresent embodiment.

Therefore, the plurality of projection parts 2-2 come into contact withthe slider 7 by equal force and have the same contact area, regardlessof the rising directions of the projection parts 2-2 due to errors inmanufacturing.

As a result, the contact areas relative to the moving body are equalizedin the motor, and the deterioration in the motor characteristics can beprevented without highly accurate processing of the projection parts.

An increase in the cost associated with highly accurate projection partscan also be prevented.

Third Embodiment

A configuration example of a manufacturing method of a vibrator in avibration type driving apparatus in a form different from the secondembodiment will be described in a third embodiment with reference toFIGS. 12 to 16.

FIG. 12 illustrates an elastic body according to the present embodiment.As in the second embodiment, the tips of the projection parts 2-2 arepart of the spheres, and lapping or grinding processing is applied tothe tips to form circular cut areas with the same diameter. A furtherrestriction in the direction of the plane of the cut area is added tothe second embodiment. Therefore, the manufacturing process is alsodifferent.

FIG. 13 is a configuration diagram of a vibration type driving apparatusof a type in which a plurality of vibrators 1 are arranged on the samecircumference, and a moving body 31 in an annular shape is moved in theA direction of FIG. 13.

To attain excellent motor characteristics in the vibration type drivingapparatus in this format, all contact parts (circular cut areas of theprojection parts 2-2) of all vibrators 1 that are in contact with themoving body 31 need to highly accurately exist on one plane. The presentembodiment is suitable for such a vibration type driving apparatus inwhich a plurality of vibrators drives a moving body.

FIG. 14 illustrates a stator portion 30 of the vibration type drivingapparatus of FIG. 13. The same number of concave step parts as thevibrators 1 are formed on an upper surface of an attachment base member32 in an annular shape, and the vibrators 1 are sunk and placed in thestep parts.

The upper surface of the attachment base member 32 and the lower surfaceof the supporting part 2-5 of the elastic body 2 are fixed by a method,such as adhesion and welding. The lowest surface (FPC 4: notillustrated) of the vibrator 1 is not in contact with the attachmentbase member 32 to avoid inhibiting the vibration of the vibration part2-3.

The feature here is that elastic bodies of a plurality of vibrators areattached to a common base member. In other words, lapping or grindingprocessing is applied to the tips of the projection parts 2-2, while thestator portion 30 is attached. FIG. 15 illustrates this.

In FIG. 15, the lap disc or grinding disc 21 rotates in the E direction.

The stator portion 30 is set so that the tips of all projection parts2-2 come into contact with the lap disc 21, and equal load is imposed onthe plurality of projection parts 2-2 in the C direction of FIG. 8.

Geometrically, the lapping or grinding processing is started, while onlythree of the projection parts 2-2 (six in FIG. 15) come into contactwith the lap disc 21.

All projection parts come into touch with the lap disc 21 after progressin the lapping or grinding process, and there is inequality in the sizesof the circular shapes of the cut areas.

However, based on the flexure of the constituent member of the statorportion 30, all projection parts 2-2 are actually pressed against thelap disc 21 at substantially equal load when the load in the C directionis imposed around the center of the stator portion 30.

Therefore, there is no inequality in the sizes of the circular shapes ofthe cut areas that poses a problem in the motor characteristics.

To prevent inequality in the amount of cutting due to the difference inthe peripheral length in the radial direction of the lap disc, arotation mechanism (not illustrated) rotates the stator portion 30 inthe D direction for the scraping.

As a result of the processing of the tips of the projection parts 2-2,the tips are on the same plane, and the tips have circular shapes withthe same area, regardless of the rising directions of the projectionparts 2-2 due to errors in manufacturing as illustrated in FIG. 16.

Although the elastic body 2 includes a plurality of projection parts 2-2in the description of the present embodiment, the nature of the presentinvention is not lost even if the number of projection parts 2-2 is one.

A configuration of the vibration type driving apparatus according to thepresent embodiment will be described with reference again to FIG. 13.

Biasing force 33 of at least three compression springs pressurizes thestator portion 30 against the moving body 31 at an appropriate pressure.

According to the configuration, all frictional contact parts (projectionparts 2-2) on the stator portion 30 follow the moving body 31, at thesame contact area and equal pressurization force relative to the lowersurface of the moving body 31.

As described, the tips of the elastic body projection parts asfrictional contact parts are formed by part of the spheres in thevibration type driving apparatus including a plurality of vibrators, andthe lapping or grinding processing is performed while the projectionparts are attached to the stator.

As a result, the contact areas relative to the moving body are equalizedin the motor, and the deterioration in the motor characteristics can beprevented, without highly accurately processing the projection parts.The increase in the cost associated with highly accurate projectionparts can also be prevented.

According to an aspect of the present invention, a vibrator, a vibrationtype driving apparatus and a manufacturing method of the vibrator thatcan improve driving performance by equalizing contact areas relative toa moving body can be realized, without the necessity to highlyaccurately process projection parts in the vibrator.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2012-095705, filed on Apr. 19, 2012, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A vibrator comprising: an electrical-mechanicalenergy converting element; and an elastic body bonded to theelectrical-mechanical energy converting element and comprising at leasttwo contact parts, wherein the at least two contact parts have convexshapes, wherein shapes of surfaces of the at least two contact parts arepart of spherical shapes, and wherein rising directions of the at leasttwo contact parts toward a member to be driven when the member is drivenare different.
 2. The vibrator according to claim 1, wherein in thevibrator, the at least two contact parts come into frictional contactwith the member to be driven, and vibration generated by the elasticbody effects relative movement between the member to be driven and thevibrator.
 3. The vibrator according to claim 1, wherein each of theshapes of the surfaces of the at least two contact parts is a shape inwhich part of a spherical shape has been removed.
 4. The vibratoraccording to claim 3, wherein surfaces of the at least two contact partsfrom which the parts of the spherical shape have been removed have asame area.
 5. A vibration type driving apparatus comprising: thevibrator according to claim 1; an attachment base member that supportsthe vibrator; and an equalizer arranged between the vibrator and theattachment base member.
 6. The vibration type driving apparatusaccording to claim 5, wherein the equalizer has a function of equalizingload on the at least two contact parts.
 7. The vibration type drivingapparatus according to claim 5, further comprising a vibration isolatingmember arranged between the equalizer and the vibrator.
 8. A vibrationtype driving apparatus comprising a plurality of vibrators according toclaim 1.